Invasive plant extends reach

February 16, 2013

Mile-a-Minute has been known for the past 20 years from Washington County where it has spread inland from the Ohio River bank it was first found on. Worse news is that it has now been found in Lawrence County. The offender's painfully sharp prickles are known to cut into human and animal skin, earning it a nickname of "tearthumb". Its aggressive growth of up to 6 inches a day should be a concern to any landowner in the area. The culprit: mile-a-minute vine (Polygonum perfoliatum).

Native to Eastern Asia, mile-a-minute vine was first introduced to Pennsylvania in the late 1930s, contaminating a shipment of rhododendrons. Despite control efforts, mile-a-minute vine has become established in Pennsylvania, Maryland, and West Virginia where it grew for several years before making it across the river via an island.

Growth of mile-a-minute vine is rapid and can easily crowd out native flowers, shrubs, and tree saplings or seedlings. This aggressive growth can prevent forest regeneration after timber harvest, interrupt Christmas tree farming, and has a potential to become a pest in plant nurseries and agricultural production. Spines along the stem and leaves can make a recreational walk through the forest painful and unpleasant. With the abundance of multiflora roses, briars, and brambles in Appalachia Ohio, the last thing the area needs is another plant covered with spines. If mile-a-minute vine is left alone and continues to spread and multiply it will hurt the economy of our region by impacting the timber industry, agricultural production, and recreation.

Mile-a-minute vine aggressively invades fields, roadsides, right-of-ways, forest edges, open woodlands, stream banks, and moist meadows. Birds are the principal long distance carriers of seeds, although it has been found to be dispersed by ants, deer, chipmunks, and squirrels. Mile-a-minute fruit is able to maintain buoyancy for up to 7 to 9 days which allows long-distance travel downstream.

The best characteristics for identifying mile-a-minute vine are its distinctive equilateral triangular shaped leaves and downward facing spines covering the underside of leaves and stems. These spines will stick to clothing and tear at skin. The leaves are approximately 1 to 3 inches wide, green, waxy, and arranged alternately up the stem. Spaced along and surrounding the stems are cup shaped structures called ocreas. From these ocreas, small white flowers bloom that eventually develop into small, metallic blue fruits about the size of a pea.